1. Field of the Invention
The present invention relates to a drive assembly, and more particularly to a drive assembly for an electric hand tool.
2. Description of Related Art
A conventional drive assembly for an electric hand tool in accordance with the prior shown in FIGS. 6-7 comprises a reversible motor (600) and a pinion gear (60) mounted on the motor shaft (not numbered) of the reversible motor (600). A hollow rotor (70) has a driven gear (61) formed on the end facing the reversible motor (600). The rotor (70) is mounted inside the hand tool such that the driven gear (61) is engaged with the pinion gear (60). A groove (72) is formed in one side of the rotor (70) to house a retainer (80). A first hook (71) extends out from each side of the rotor (70) adjacent to the side with the groove (72). A second hook (81) corresponding to the first hook (71) on the rotor (70) is formed on each end of the retainer (80). A spring is connected to each corresponding pair of first hooks (71) and second hooks (81). One end of a spring (91) is hooked on a first hook (71), and the other is hooked on the corresponding second hook (81). A drive block (90) is mounted in the rotor (70) inside the retainer (80). A main shaft (92) is rotatably mounted in the rotor (70). A transmission block (921) is securely mounted on one end of the main shaft (92) in the rotor (70). The drive block (90) drives the transmission block (921) and the main shaft (92) when the rotor (70) is rotated by the reversible motor (600).
The drive assembly for an electric hand tool as described above has several disadvantages.
1. The conventional drive assembly for an electric hand tool is noisy when the gears of the electric hand tool are operated, especially when changing the direction of rotation. PA1 2. The whole rotor must be replaced with a new one when any one of the gears is broken. It will take a lot of time and costs a lot of money.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional drive assembly for an electric hand tool.